In order to enhance the security of an office or home, the door of the office or home is generally provided with an auxiliary lock, which is installed in a preformed slot in the door. However, it is often difficult to find an auxiliary lock which is designed to fit the preformed slot in the door. As a result, a new slot must be formed in the door to accommodate the auxiliary lock. The formation of the new slot in the door can cost additional money and undermine the structural integrity and the esthetic effect of the door.